This invention provides a chuck head for automatic machine tools characterised by the particular arrangement of the parts whereby a unit which is extremely compact in comparison with other known similar units is obtained.
The head according to the invention is designed to be used in automatic or robot machine tools, in which the end member performs the various machining operations. As is known, these devices, which are used for high precision machining in repetitive cycles, provide a tool mounted on a support which has several degrees of freedom and whose movements are controlled by electronc means of a known type.
In some cases the tool is mounted on a head or chuck head which consists of a fork mounted at the end of an arm which can move about a number of axes, on which an electrically driven chuck is mounted.
A head of this type is described, for example, in U.S. Pat. No. 4,652,190.
The invention relates to this type of head.
The problem which must be solved arises from the difficulty which is frequently encountered when the tool must work in a confined space, and it is then desirable to have tools of the smallest possible dimensions.
In this type of equipment it is necessary to be able to impart movements about various axes, often five or more, to the tool, as a result of which it is necessary to make use of numerous transmission devices whose size constitutes a considerable obstacle to reduction of the dimensions of the whole.
In particular, in order to control angular movements of the electrically driven chuck or spindle housing with respect to the fork on which it is mounted use is made of endless screw and helical wheel devices which must necessarily be mounted within the fork where they enable the latter to rotate with respect to the supporting arm. This type of transmission is also subject to increased wear in comparison with the other components and has limited rigidity. There is therefore a need to have means which make it possible to reduce the dimensions of the unit as a whole without prejudicing its satisfactory operation while at the same time retaining the required accuracy and rigidity characteristics.